The invention relates to a Wireless Local Loop System (WLL), i.e., a radio system providing a wireless local loop, in which subscriber stations are connected over a radio connection via base stations and a subscriber network element to an exchange of a public switched telephone network. Any conventional user interface, i.e., telephone set, can be connected to a WLL system via a special terminal equipment, whereby the radio path is invisible to the user.
The subscribers of a WLL system must have access to a register recall facility and subscriber facilities requiring it, in the same way as the subscribers of a normal wired network. To render the radio path invisible to the user of a WLL subscriber station, it must be possible to use the station in exactly the same way as a conventional wired telephone. This means that a register recall must be implemented such that the subscriber first presses the R-key, waits until a dial tone is transmitted to him, and then dials the desired digits via the user interface.
WLL systems are usually based on a known cellular radio system, such as the NMT-450i system (Nordic Mobile Telephone), whereby their signal is usually similar to that of the cellular radio system concerned. It is thus advantageous that subscriber stations of the cellular radio system on which the WLL system is based can also be used in the WLL system. For example, according to the specifications of the NMT-450i system, a register recall is performed by first dial the desired digits to the memory of the telephone and then pressing the R-key to effect a register recall. When an NMT phone is used, the register recall procedures are performed in the reverse order as compared with a fixed, wired network, which is problematic to the subscriber network element of the system.